1git(1) 2====== 3 4NAME 5---- 6git - the stupid content tracker 7 8 9SYNOPSIS 10-------- 11[verse] 12'git' [--version] [--exec-path[=GIT_EXEC_PATH]] [--html-path] 13 [-p|--paginate|--no-pager] [--no-replace-objects] 14 [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE] 15 [-c name=value] 16 [--help] COMMAND [ARGS] 17 18DESCRIPTION 19----------- 20Git is a fast, scalable, distributed revision control system with an 21unusually rich command set that provides both high-level operations 22and full access to internals. 23 24See linkgit:gittutorial[7] to get started, then see 25link:everyday.html[Everyday Git] for a useful minimum set of commands, and 26"man git-commandname" for documentation of each command. CVS users may 27also want to read linkgit:gitcvs-migration[7]. See 28the link:user-manual.html[Git User's Manual] for a more in-depth 29introduction. 30 31The COMMAND is either a name of a Git command (see below) or an alias 32as defined in the configuration file (see linkgit:git-config[1]). 33 34Formatted and hyperlinked version of the latest git 35documentation can be viewed at 36`http://www.kernel.org/pub/software/scm/git/docs/`. 37 38ifdef::stalenotes[] 39[NOTE] 40============ 41 42You are reading the documentation for the latest (possibly 43unreleased) version of git, that is available from 'master' 44branch of the `git.git` repository. 45Documentation for older releases are available here: 46 47* link:v1.7.2.3/git.html[documentation for release 1.7.2.3] 48 49* release notes for 50 link:RelNotes-1.7.2.3.txt[1.7.2.3], 51 link:RelNotes-1.7.2.2.txt[1.7.2.2], 52 link:RelNotes-1.7.2.1.txt[1.7.2.1], 53 link:RelNotes-1.7.2.txt[1.7.2]. 54 55* link:v1.7.1.2/git.html[documentation for release 1.7.1.2] 56 57* release notes for 58 link:RelNotes-1.7.1.2.txt[1.7.1.2], 59 link:RelNotes-1.7.1.1.txt[1.7.1.1], 60 link:RelNotes-1.7.1.txt[1.7.1]. 61 62* link:v1.7.0.7/git.html[documentation for release 1.7.0.7] 63 64* release notes for 65 link:RelNotes-1.7.0.7.txt[1.7.0.7], 66 link:RelNotes-1.7.0.6.txt[1.7.0.6], 67 link:RelNotes-1.7.0.5.txt[1.7.0.5], 68 link:RelNotes-1.7.0.4.txt[1.7.0.4], 69 link:RelNotes-1.7.0.3.txt[1.7.0.3], 70 link:RelNotes-1.7.0.2.txt[1.7.0.2], 71 link:RelNotes-1.7.0.1.txt[1.7.0.1], 72 link:RelNotes-1.7.0.txt[1.7.0]. 73 74* link:v1.6.6.2/git.html[documentation for release 1.6.6.2] 75 76* release notes for 77 link:RelNotes-1.6.6.2.txt[1.6.6.2], 78 link:RelNotes-1.6.6.1.txt[1.6.6.1], 79 link:RelNotes-1.6.6.txt[1.6.6]. 80 81* link:v1.6.5.8/git.html[documentation for release 1.6.5.8] 82 83* release notes for 84 link:RelNotes-1.6.5.8.txt[1.6.5.8], 85 link:RelNotes-1.6.5.7.txt[1.6.5.7], 86 link:RelNotes-1.6.5.6.txt[1.6.5.6], 87 link:RelNotes-1.6.5.5.txt[1.6.5.5], 88 link:RelNotes-1.6.5.4.txt[1.6.5.4], 89 link:RelNotes-1.6.5.3.txt[1.6.5.3], 90 link:RelNotes-1.6.5.2.txt[1.6.5.2], 91 link:RelNotes-1.6.5.1.txt[1.6.5.1], 92 link:RelNotes-1.6.5.txt[1.6.5]. 93 94* link:v1.6.4.4/git.html[documentation for release 1.6.4.4] 95 96* release notes for 97 link:RelNotes-1.6.4.4.txt[1.6.4.4], 98 link:RelNotes-1.6.4.3.txt[1.6.4.3], 99 link:RelNotes-1.6.4.2.txt[1.6.4.2], 100 link:RelNotes-1.6.4.1.txt[1.6.4.1], 101 link:RelNotes-1.6.4.txt[1.6.4]. 102 103* link:v1.6.3.4/git.html[documentation for release 1.6.3.4] 104 105* release notes for 106 link:RelNotes-1.6.3.4.txt[1.6.3.4], 107 link:RelNotes-1.6.3.3.txt[1.6.3.3], 108 link:RelNotes-1.6.3.2.txt[1.6.3.2], 109 link:RelNotes-1.6.3.1.txt[1.6.3.1], 110 link:RelNotes-1.6.3.txt[1.6.3]. 111 112* release notes for 113 link:RelNotes-1.6.2.5.txt[1.6.2.5], 114 link:RelNotes-1.6.2.4.txt[1.6.2.4], 115 link:RelNotes-1.6.2.3.txt[1.6.2.3], 116 link:RelNotes-1.6.2.2.txt[1.6.2.2], 117 link:RelNotes-1.6.2.1.txt[1.6.2.1], 118 link:RelNotes-1.6.2.txt[1.6.2]. 119 120* link:v1.6.1.3/git.html[documentation for release 1.6.1.3] 121 122* release notes for 123 link:RelNotes-1.6.1.3.txt[1.6.1.3], 124 link:RelNotes-1.6.1.2.txt[1.6.1.2], 125 link:RelNotes-1.6.1.1.txt[1.6.1.1], 126 link:RelNotes-1.6.1.txt[1.6.1]. 127 128* link:v1.6.0.6/git.html[documentation for release 1.6.0.6] 129 130* release notes for 131 link:RelNotes-1.6.0.6.txt[1.6.0.6], 132 link:RelNotes-1.6.0.5.txt[1.6.0.5], 133 link:RelNotes-1.6.0.4.txt[1.6.0.4], 134 link:RelNotes-1.6.0.3.txt[1.6.0.3], 135 link:RelNotes-1.6.0.2.txt[1.6.0.2], 136 link:RelNotes-1.6.0.1.txt[1.6.0.1], 137 link:RelNotes-1.6.0.txt[1.6.0]. 138 139* link:v1.5.6.6/git.html[documentation for release 1.5.6.6] 140 141* release notes for 142 link:RelNotes-1.5.6.6.txt[1.5.6.6], 143 link:RelNotes-1.5.6.5.txt[1.5.6.5], 144 link:RelNotes-1.5.6.4.txt[1.5.6.4], 145 link:RelNotes-1.5.6.3.txt[1.5.6.3], 146 link:RelNotes-1.5.6.2.txt[1.5.6.2], 147 link:RelNotes-1.5.6.1.txt[1.5.6.1], 148 link:RelNotes-1.5.6.txt[1.5.6]. 149 150* link:v1.5.5.6/git.html[documentation for release 1.5.5.6] 151 152* release notes for 153 link:RelNotes-1.5.5.6.txt[1.5.5.6], 154 link:RelNotes-1.5.5.5.txt[1.5.5.5], 155 link:RelNotes-1.5.5.4.txt[1.5.5.4], 156 link:RelNotes-1.5.5.3.txt[1.5.5.3], 157 link:RelNotes-1.5.5.2.txt[1.5.5.2], 158 link:RelNotes-1.5.5.1.txt[1.5.5.1], 159 link:RelNotes-1.5.5.txt[1.5.5]. 160 161* link:v1.5.4.7/git.html[documentation for release 1.5.4.7] 162 163* release notes for 164 link:RelNotes-1.5.4.7.txt[1.5.4.7], 165 link:RelNotes-1.5.4.6.txt[1.5.4.6], 166 link:RelNotes-1.5.4.5.txt[1.5.4.5], 167 link:RelNotes-1.5.4.4.txt[1.5.4.4], 168 link:RelNotes-1.5.4.3.txt[1.5.4.3], 169 link:RelNotes-1.5.4.2.txt[1.5.4.2], 170 link:RelNotes-1.5.4.1.txt[1.5.4.1], 171 link:RelNotes-1.5.4.txt[1.5.4]. 172 173* link:v1.5.3.8/git.html[documentation for release 1.5.3.8] 174 175* release notes for 176 link:RelNotes-1.5.3.8.txt[1.5.3.8], 177 link:RelNotes-1.5.3.7.txt[1.5.3.7], 178 link:RelNotes-1.5.3.6.txt[1.5.3.6], 179 link:RelNotes-1.5.3.5.txt[1.5.3.5], 180 link:RelNotes-1.5.3.4.txt[1.5.3.4], 181 link:RelNotes-1.5.3.3.txt[1.5.3.3], 182 link:RelNotes-1.5.3.2.txt[1.5.3.2], 183 link:RelNotes-1.5.3.1.txt[1.5.3.1], 184 link:RelNotes-1.5.3.txt[1.5.3]. 185 186* link:v1.5.2.5/git.html[documentation for release 1.5.2.5] 187 188* release notes for 189 link:RelNotes-1.5.2.5.txt[1.5.2.5], 190 link:RelNotes-1.5.2.4.txt[1.5.2.4], 191 link:RelNotes-1.5.2.3.txt[1.5.2.3], 192 link:RelNotes-1.5.2.2.txt[1.5.2.2], 193 link:RelNotes-1.5.2.1.txt[1.5.2.1], 194 link:RelNotes-1.5.2.txt[1.5.2]. 195 196* link:v1.5.1.6/git.html[documentation for release 1.5.1.6] 197 198* release notes for 199 link:RelNotes-1.5.1.6.txt[1.5.1.6], 200 link:RelNotes-1.5.1.5.txt[1.5.1.5], 201 link:RelNotes-1.5.1.4.txt[1.5.1.4], 202 link:RelNotes-1.5.1.3.txt[1.5.1.3], 203 link:RelNotes-1.5.1.2.txt[1.5.1.2], 204 link:RelNotes-1.5.1.1.txt[1.5.1.1], 205 link:RelNotes-1.5.1.txt[1.5.1]. 206 207* link:v1.5.0.7/git.html[documentation for release 1.5.0.7] 208 209* release notes for 210 link:RelNotes-1.5.0.7.txt[1.5.0.7], 211 link:RelNotes-1.5.0.6.txt[1.5.0.6], 212 link:RelNotes-1.5.0.5.txt[1.5.0.5], 213 link:RelNotes-1.5.0.3.txt[1.5.0.3], 214 link:RelNotes-1.5.0.2.txt[1.5.0.2], 215 link:RelNotes-1.5.0.1.txt[1.5.0.1], 216 link:RelNotes-1.5.0.txt[1.5.0]. 217 218* documentation for release link:v1.4.4.4/git.html[1.4.4.4], 219 link:v1.3.3/git.html[1.3.3], 220 link:v1.2.6/git.html[1.2.6], 221 link:v1.0.13/git.html[1.0.13]. 222 223============ 224 225endif::stalenotes[] 226 227OPTIONS 228------- 229--version:: 230 Prints the git suite version that the 'git' program came from. 231 232--help:: 233 Prints the synopsis and a list of the most commonly used 234 commands. If the option '--all' or '-a' is given then all 235 available commands are printed. If a git command is named this 236 option will bring up the manual page for that command. 237+ 238Other options are available to control how the manual page is 239displayed. See linkgit:git-help[1] for more information, 240because `git --help ...` is converted internally into `git 241help ...`. 242 243-c <name>=<value>:: 244 Pass a configuration parameter to the command. The value 245 given will override values from configuration files. 246 The <name> is expected in the same format as listed by 247 'git config' (subkeys separated by dots). 248 249--exec-path:: 250 Path to wherever your core git programs are installed. 251 This can also be controlled by setting the GIT_EXEC_PATH 252 environment variable. If no path is given, 'git' will print 253 the current setting and then exit. 254 255--html-path:: 256 Print the path to wherever your git HTML documentation is installed 257 and exit. 258 259-p:: 260--paginate:: 261 Pipe all output into 'less' (or if set, $PAGER) if standard 262 output is a terminal. This overrides the `pager.<cmd>` 263 configuration options (see the "Configuration Mechanism" section 264 below). 265 266--no-pager:: 267 Do not pipe git output into a pager. 268 269--git-dir=<path>:: 270 Set the path to the repository. This can also be controlled by 271 setting the GIT_DIR environment variable. It can be an absolute 272 path or relative path to current working directory. 273 274--work-tree=<path>:: 275 Set the path to the working tree. The value will not be 276 used in combination with repositories found automatically in 277 a .git directory (i.e. $GIT_DIR is not set). 278 This can also be controlled by setting the GIT_WORK_TREE 279 environment variable and the core.worktree configuration 280 variable. It can be an absolute path or relative path to 281 the directory specified by --git-dir or GIT_DIR. 282 Note: If --git-dir or GIT_DIR are specified but none of 283 --work-tree, GIT_WORK_TREE and core.worktree is specified, 284 the current working directory is regarded as the top directory 285 of your working tree. 286 287--bare:: 288 Treat the repository as a bare repository. If GIT_DIR 289 environment is not set, it is set to the current working 290 directory. 291 292--no-replace-objects:: 293 Do not use replacement refs to replace git objects. See 294 linkgit:git-replace[1] for more information. 295 296 297FURTHER DOCUMENTATION 298--------------------- 299 300See the references above to get started using git. The following is 301probably more detail than necessary for a first-time user. 302 303The link:user-manual.html#git-concepts[git concepts chapter of the 304user-manual] and linkgit:gitcore-tutorial[7] both provide 305introductions to the underlying git architecture. 306 307See linkgit:gitworkflows[7] for an overview of recommended workflows. 308 309See also the link:howto-index.html[howto] documents for some useful 310examples. 311 312The internals are documented in the 313link:technical/api-index.html[GIT API documentation]. 314 315GIT COMMANDS 316------------ 317 318We divide git into high level ("porcelain") commands and low level 319("plumbing") commands. 320 321High-level commands (porcelain) 322------------------------------- 323 324We separate the porcelain commands into the main commands and some 325ancillary user utilities. 326 327Main porcelain commands 328~~~~~~~~~~~~~~~~~~~~~~~ 329 330include::cmds-mainporcelain.txt[] 331 332Ancillary Commands 333~~~~~~~~~~~~~~~~~~ 334Manipulators: 335 336include::cmds-ancillarymanipulators.txt[] 337 338Interrogators: 339 340include::cmds-ancillaryinterrogators.txt[] 341 342 343Interacting with Others 344~~~~~~~~~~~~~~~~~~~~~~~ 345 346These commands are to interact with foreign SCM and with other 347people via patch over e-mail. 348 349include::cmds-foreignscminterface.txt[] 350 351 352Low-level commands (plumbing) 353----------------------------- 354 355Although git includes its 356own porcelain layer, its low-level commands are sufficient to support 357development of alternative porcelains. Developers of such porcelains 358might start by reading about linkgit:git-update-index[1] and 359linkgit:git-read-tree[1]. 360 361The interface (input, output, set of options and the semantics) 362to these low-level commands are meant to be a lot more stable 363than Porcelain level commands, because these commands are 364primarily for scripted use. The interface to Porcelain commands 365on the other hand are subject to change in order to improve the 366end user experience. 367 368The following description divides 369the low-level commands into commands that manipulate objects (in 370the repository, index, and working tree), commands that interrogate and 371compare objects, and commands that move objects and references between 372repositories. 373 374 375Manipulation commands 376~~~~~~~~~~~~~~~~~~~~~ 377 378include::cmds-plumbingmanipulators.txt[] 379 380 381Interrogation commands 382~~~~~~~~~~~~~~~~~~~~~~ 383 384include::cmds-plumbinginterrogators.txt[] 385 386In general, the interrogate commands do not touch the files in 387the working tree. 388 389 390Synching repositories 391~~~~~~~~~~~~~~~~~~~~~ 392 393include::cmds-synchingrepositories.txt[] 394 395The following are helper commands used by the above; end users 396typically do not use them directly. 397 398include::cmds-synchelpers.txt[] 399 400 401Internal helper commands 402~~~~~~~~~~~~~~~~~~~~~~~~ 403 404These are internal helper commands used by other commands; end 405users typically do not use them directly. 406 407include::cmds-purehelpers.txt[] 408 409 410Configuration Mechanism 411----------------------- 412 413Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file 414is used to hold per-repository configuration options. It is a 415simple text file modeled after `.ini` format familiar to some 416people. Here is an example: 417 418------------ 419# 420# A '#' or ';' character indicates a comment. 421# 422 423; core variables 424[core] 425 ; Don't trust file modes 426 filemode = false 427 428; user identity 429[user] 430 name = "Junio C Hamano" 431 email = "junkio@twinsun.com" 432 433------------ 434 435Various commands read from the configuration file and adjust 436their operation accordingly. See linkgit:git-config[1] for a 437list. 438 439 440Identifier Terminology 441---------------------- 442<object>:: 443 Indicates the object name for any type of object. 444 445<blob>:: 446 Indicates a blob object name. 447 448<tree>:: 449 Indicates a tree object name. 450 451<commit>:: 452 Indicates a commit object name. 453 454<tree-ish>:: 455 Indicates a tree, commit or tag object name. A 456 command that takes a <tree-ish> argument ultimately wants to 457 operate on a <tree> object but automatically dereferences 458 <commit> and <tag> objects that point at a <tree>. 459 460<commit-ish>:: 461 Indicates a commit or tag object name. A 462 command that takes a <commit-ish> argument ultimately wants to 463 operate on a <commit> object but automatically dereferences 464 <tag> objects that point at a <commit>. 465 466<type>:: 467 Indicates that an object type is required. 468 Currently one of: `blob`, `tree`, `commit`, or `tag`. 469 470<file>:: 471 Indicates a filename - almost always relative to the 472 root of the tree structure `GIT_INDEX_FILE` describes. 473 474Symbolic Identifiers 475-------------------- 476Any git command accepting any <object> can also use the following 477symbolic notation: 478 479HEAD:: 480 indicates the head of the current branch (i.e. the 481 contents of `$GIT_DIR/HEAD`). 482 483<tag>:: 484 a valid tag 'name' 485 (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`). 486 487<head>:: 488 a valid head 'name' 489 (i.e. the contents of `$GIT_DIR/refs/heads/<head>`). 490 491For a more complete list of ways to spell object names, see 492"SPECIFYING REVISIONS" section in linkgit:gitrevisions[1]. 493 494 495File/Directory Structure 496------------------------ 497 498Please see the linkgit:gitrepository-layout[5] document. 499 500Read linkgit:githooks[5] for more details about each hook. 501 502Higher level SCMs may provide and manage additional information in the 503`$GIT_DIR`. 504 505 506Terminology 507----------- 508Please see linkgit:gitglossary[7]. 509 510 511Environment Variables 512--------------------- 513Various git commands use the following environment variables: 514 515The git Repository 516~~~~~~~~~~~~~~~~~~ 517These environment variables apply to 'all' core git commands. Nb: it 518is worth noting that they may be used/overridden by SCMS sitting above 519git so take care if using Cogito etc. 520 521'GIT_INDEX_FILE':: 522 This environment allows the specification of an alternate 523 index file. If not specified, the default of `$GIT_DIR/index` 524 is used. 525 526'GIT_OBJECT_DIRECTORY':: 527 If the object storage directory is specified via this 528 environment variable then the sha1 directories are created 529 underneath - otherwise the default `$GIT_DIR/objects` 530 directory is used. 531 532'GIT_ALTERNATE_OBJECT_DIRECTORIES':: 533 Due to the immutable nature of git objects, old objects can be 534 archived into shared, read-only directories. This variable 535 specifies a ":" separated (on Windows ";" separated) list 536 of git object directories which can be used to search for git 537 objects. New objects will not be written to these directories. 538 539'GIT_DIR':: 540 If the 'GIT_DIR' environment variable is set then it 541 specifies a path to use instead of the default `.git` 542 for the base of the repository. 543 544'GIT_WORK_TREE':: 545 Set the path to the working tree. The value will not be 546 used in combination with repositories found automatically in 547 a .git directory (i.e. $GIT_DIR is not set). 548 This can also be controlled by the '--work-tree' command line 549 option and the core.worktree configuration variable. 550 551'GIT_CEILING_DIRECTORIES':: 552 This should be a colon-separated list of absolute paths. 553 If set, it is a list of directories that git should not chdir 554 up into while looking for a repository directory. 555 It will not exclude the current working directory or 556 a GIT_DIR set on the command line or in the environment. 557 (Useful for excluding slow-loading network directories.) 558 559'GIT_DISCOVERY_ACROSS_FILESYSTEM':: 560 When run in a directory that does not have ".git" repository 561 directory, git tries to find such a directory in the parent 562 directories to find the top of the working tree, but by default it 563 does not cross filesystem boundaries. This environment variable 564 can be set to true to tell git not to stop at filesystem 565 boundaries. Like 'GIT_CEILING_DIRECTORIES', this will not affect 566 an explicit repository directory set via 'GIT_DIR' or on the 567 command line. 568 569git Commits 570~~~~~~~~~~~ 571'GIT_AUTHOR_NAME':: 572'GIT_AUTHOR_EMAIL':: 573'GIT_AUTHOR_DATE':: 574'GIT_COMMITTER_NAME':: 575'GIT_COMMITTER_EMAIL':: 576'GIT_COMMITTER_DATE':: 577'EMAIL':: 578 see linkgit:git-commit-tree[1] 579 580git Diffs 581~~~~~~~~~ 582'GIT_DIFF_OPTS':: 583 Only valid setting is "--unified=??" or "-u??" to set the 584 number of context lines shown when a unified diff is created. 585 This takes precedence over any "-U" or "--unified" option 586 value passed on the git diff command line. 587 588'GIT_EXTERNAL_DIFF':: 589 When the environment variable 'GIT_EXTERNAL_DIFF' is set, the 590 program named by it is called, instead of the diff invocation 591 described above. For a path that is added, removed, or modified, 592 'GIT_EXTERNAL_DIFF' is called with 7 parameters: 593 594 path old-file old-hex old-mode new-file new-hex new-mode 595+ 596where: 597 598 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the 599 contents of <old|new>, 600 <old|new>-hex:: are the 40-hexdigit SHA1 hashes, 601 <old|new>-mode:: are the octal representation of the file modes. 602 603+ 604The file parameters can point at the user's working file 605(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file` 606when a new file is added), or a temporary file (e.g. `old-file` in the 607index). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the 608temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits. 609+ 610For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1 611parameter, <path>. 612 613other 614~~~~~ 615'GIT_MERGE_VERBOSITY':: 616 A number controlling the amount of output shown by 617 the recursive merge strategy. Overrides merge.verbosity. 618 See linkgit:git-merge[1] 619 620'GIT_PAGER':: 621 This environment variable overrides `$PAGER`. If it is set 622 to an empty string or to the value "cat", git will not launch 623 a pager. See also the `core.pager` option in 624 linkgit:git-config[1]. 625 626'GIT_SSH':: 627 If this environment variable is set then 'git fetch' 628 and 'git push' will use this command instead 629 of 'ssh' when they need to connect to a remote system. 630 The '$GIT_SSH' command will be given exactly two arguments: 631 the 'username@host' (or just 'host') from the URL and the 632 shell command to execute on that remote system. 633+ 634To pass options to the program that you want to list in GIT_SSH 635you will need to wrap the program and options into a shell script, 636then set GIT_SSH to refer to the shell script. 637+ 638Usually it is easier to configure any desired options through your 639personal `.ssh/config` file. Please consult your ssh documentation 640for further details. 641 642'GIT_FLUSH':: 643 If this environment variable is set to "1", then commands such 644 as 'git blame' (in incremental mode), 'git rev-list', 'git log', 645 and 'git whatchanged' will force a flush of the output stream 646 after each commit-oriented record have been flushed. If this 647 variable is set to "0", the output of these commands will be done 648 using completely buffered I/O. If this environment variable is 649 not set, git will choose buffered or record-oriented flushing 650 based on whether stdout appears to be redirected to a file or not. 651 652'GIT_TRACE':: 653 If this variable is set to "1", "2" or "true" (comparison 654 is case insensitive), git will print `trace:` messages on 655 stderr telling about alias expansion, built-in command 656 execution and external command execution. 657 If this variable is set to an integer value greater than 1 658 and lower than 10 (strictly) then git will interpret this 659 value as an open file descriptor and will try to write the 660 trace messages into this file descriptor. 661 Alternatively, if this variable is set to an absolute path 662 (starting with a '/' character), git will interpret this 663 as a file path and will try to write the trace messages 664 into it. 665 666Discussion[[Discussion]] 667------------------------ 668 669More detail on the following is available from the 670link:user-manual.html#git-concepts[git concepts chapter of the 671user-manual] and linkgit:gitcore-tutorial[7]. 672 673A git project normally consists of a working directory with a ".git" 674subdirectory at the top level. The .git directory contains, among other 675things, a compressed object database representing the complete history 676of the project, an "index" file which links that history to the current 677contents of the working tree, and named pointers into that history such 678as tags and branch heads. 679 680The object database contains objects of three main types: blobs, which 681hold file data; trees, which point to blobs and other trees to build up 682directory hierarchies; and commits, which each reference a single tree 683and some number of parent commits. 684 685The commit, equivalent to what other systems call a "changeset" or 686"version", represents a step in the project's history, and each parent 687represents an immediately preceding step. Commits with more than one 688parent represent merges of independent lines of development. 689 690All objects are named by the SHA1 hash of their contents, normally 691written as a string of 40 hex digits. Such names are globally unique. 692The entire history leading up to a commit can be vouched for by signing 693just that commit. A fourth object type, the tag, is provided for this 694purpose. 695 696When first created, objects are stored in individual files, but for 697efficiency may later be compressed together into "pack files". 698 699Named pointers called refs mark interesting points in history. A ref 700may contain the SHA1 name of an object or the name of another ref. Refs 701with names beginning `ref/head/` contain the SHA1 name of the most 702recent commit (or "head") of a branch under development. SHA1 names of 703tags of interest are stored under `ref/tags/`. A special ref named 704`HEAD` contains the name of the currently checked-out branch. 705 706The index file is initialized with a list of all paths and, for each 707path, a blob object and a set of attributes. The blob object represents 708the contents of the file as of the head of the current branch. The 709attributes (last modified time, size, etc.) are taken from the 710corresponding file in the working tree. Subsequent changes to the 711working tree can be found by comparing these attributes. The index may 712be updated with new content, and new commits may be created from the 713content stored in the index. 714 715The index is also capable of storing multiple entries (called "stages") 716for a given pathname. These stages are used to hold the various 717unmerged version of a file when a merge is in progress. 718 719Authors 720------- 721* git's founding father is Linus Torvalds <torvalds@osdl.org>. 722* The current git nurse is Junio C Hamano <gitster@pobox.com>. 723* The git potty was written by Andreas Ericsson <ae@op5.se>. 724* General upbringing is handled by the git-list <git@vger.kernel.org>. 725 726Documentation 727-------------- 728The documentation for git suite was started by David Greaves 729<david@dgreaves.com>, and later enhanced greatly by the 730contributors on the git-list <git@vger.kernel.org>. 731 732Reporting Bugs 733-------------- 734 735Report bugs to the Git mailing list <git@vger.kernel.org> where the 736development and maintenance is primarily done. You do not have to be 737subscribed to the list to send a message there. 738 739SEE ALSO 740-------- 741linkgit:gittutorial[7], linkgit:gittutorial-2[7], 742link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7], 743linkgit:gitglossary[7], linkgit:gitcore-tutorial[7], 744linkgit:gitcli[7], link:user-manual.html[The Git User's Manual], 745linkgit:gitworkflows[7] 746 747GIT 748--- 749Part of the linkgit:git[1] suite